Solvent (ionic liquid) impregnated resin-based extraction coupled with dynamic ultrasonic desorption for separation and concentration of four herbicides in environmental water

Removal of reactive orange 16 and reactive green 19 using Cyphos IL101-impregnated Amberlite XAD7HP resin in batch and recirculating stirrer vessel

Reactive dyes are highly soluble in water, and carcinogenic. Therefore, it is essential to remove these dyes from their aqueous solutions. This study focused on the simultaneous removal of reactive orange 16 (RO) and reactive green 19 (RG) dyes from their binary dye solution using Cyphos IL101-impregnated Amberlite XAD7HP resin (ILX7) in batch and recirculating stirrer vessel (RSV). In the batch study, the experimental operating conditions were designed by using central composite design of response surface methodology. Influence of important input variables (RO dye concentration, RG dye concentration, pH, and resin dosage) on the dye adsorption was studied and their values were optimized. At the optimum values of input variables, equilibrium, kinetic, and thermodynamic studies were performed for the binary dye mixture. The equilibrium and kinetic adsorption data were best fitted with extended-Freundlich and pseudo-second-order models, respectively. Now to intensify the process, continuous studies were performed in a RSV at optimum conditions and at different flow rates and stirring speeds. The impregnated resin was regenerated by using 80% v/v ethanol and successfully reused up to 3 cycles with slight decrease in the adsorption capacity.

Removal of triazine-based herbicides on specific polymeric sorbent: fixed bed column studies

The porous material containing carboxyl groups was investigated in fixed bed system for the triazine-based herbicides removal from aqueous solution. In order to obtain adsorbent capable of generating specific interactions with triazines, the poly(divinylbenzene) was synthesized in radical suspension polymerization and then was modified with maleic anhydride in Diels-Alder reaction with subsequent base hydrolysis. The introduction of carboxyl groups into polymer structure resulted in obtaining specific interactions, such as hydrogen bonds between modified poly(divinylbenzene) and triazines, therefore the selectivity and the high adsorption capacity towards terbuthylazine, propazine, atrazine and simazine was observed. The total and usable adsorptive capacities, the breakthrough and exhaustion times, the coefficients of sphericity of isoplanes, the heights of adsorption fronts and the mass exchange moving rates were calculated based on the analysis of the breakthrough curves. Results show that the best sorption parameters in dynamic conditions were achieved for terbuthylazine and propazine. For them the highest values of adsorptive capacities, the smallest heights of mass transfer fronts and their slow movement along the bed height were obtained. The use of ethanol for herbicides elution provided a high recovery degree of adsorbed substances. Reusability of investigated polymer bed was studied in three adsorption/desorption cycles.

Agarose- and alginate-based biopolymers for sample preparation: Excellent green extraction tools for this century

Recently, there has been considerable interest in the use of miniaturized sample preparation techniques before the chromatographic monitoring of the analytes in unknown complex compositions. The use of biopolymer-based sorbents in solid-phase microextraction techniques has achieved a good reputation. A great variety of polysaccharides can be extracted from marine plants or microorganisms. Seaweeds are the major sources of polysaccharides such as alginate, agar, agarose, as well as carrageenans. Agarose and alginate (green biopolymers) have been manipulated for different microextraction approaches. The present review is focused on the classification of biopolymer and their applications in multidisciplinary research. Besides, efforts have been made to discuss the state-of-the-art of the new microextraction techniques that utilize commercial biopolymer interfaces such as agarose in liquid-phase microextraction and solid-phase microextraction.